Incisors Flashcards
Number of incisors in each quadrant
2 incisors in each quadrant: 1 central 1 lateral
Total 8 incisors
Do the central and lateral incisors of the same arch have more similarities
Yes
Do the mx central and mn central incisors have more similarities
No
General difference of maxillary vs mandibular incisors
Mx larger than mn
In the mn arch: mn LI larger than CI
In the mx arch: mx CI larger than LI
Function of incisors
- mastication
- aesthetics
- speech
Numbers of incisors
FDI: 11 12, 21 22, 31 32, 41 42
Universal numbering system 7 8 9 10 etc
Palmers notation similar to fdi with that L shaped thing to determine which quad is it in
General dimensions of mx ci
labial view
Overall length: 24.3mm
Root > crown by 2-3mm
Crown length > crown width
mesial view
incisocervical crown dimension > labiolingual crown dimension by 3-4.1mm
Mx ci crown dimension labial view
Incisocervical dimension > mesiodistal dimension
Mx ci labial crown outline form common exam qn
Trapezoidal
Incisal edge of ci
Almost straight mesiodistally except for mamelons in newly erupted incisors
Mesioincisal angle vs disto incisal angle labial view
Mesioincisal angle is sharper than distoincisal angle
Mesioincisal angle is almost 90 degrees but still ACUTE
Distoincisal angle is more rounded, OBTUSE
contacts of mx ci
Mesial proximal contact: incisal 1/3 near mesioincisal angle
mesial proximal contact is roughly ovoid (hence greater incisocervical dimension)
Distal proximal contact: incisal 1/3 near junction with middle 1/3
distal proximal contact is smaller and located more cervically than the mesial proximal contacct
distal vs mesial outline of crown (clue: the mesioincisal vs distoincisal angle)
distal outline is more convex and curved than the mesial surface
mesial surface is almost straight
got developmental depressions? mx ci
yes, 2 labial developmental depressions fading out in mid 1/3 of crown
labial heights of contour of mx ci
m shaped, outline giving rise to the 2 labial depressions
height of contour on labial surface is on the cervical 3rd of the tooth
mx ci got imbrication lines?
yes at the cervical 3rd of tooth
root form features of mx ci
cone shaped tapering palatally, broader mesiodistally on the labial surface
cross section of a rounded triangle becoming ovoid at midroot
apex is relatively blunted
mx ci crown outline form from incisal view
roughly triangular
mx ci incisal edge
relatively straight, slightly curved mesiodistally
distance between the labioincisal and linguoincisal ling angle is 1.5 to 2mm
mx ci lingual fossa ?
yes, one shallow and big concavity incisal 1/2 to 2/3 of the palatal surface
mx ci lingual surface characteristics other than the large ass fossa
marginal ridge marking the mesial and distal borders of the tooth -> rmb u had a hard time making this
mesial marginal ridge just like the mesial surface of the crown (when looked at labially) is nearly straight , having greater incisocervical dimension than distal marginal ridge which is more curved
accessory ridge in a W shape, not everyone has (64%)
mx ci cingulum
cingulum definition: rounded convex prominence at palatal cervical 3rd
located towards distal
is broad mesiodistally
trait of central incisors that are different from other teeth
ci are usually the only teeth that do not occlude with the opposing teeth when jaws are closed
mx ci crown outline form from mesial surface
triangle, wedge shaped, chisel shaped
incisal ridge position on mx ci
based on the mesial view, incisal edge lies on the long axis of the tooth / labial to it
incisal edge or incisal ridge?
incisal ridge is usually in newly erupted tooth and often with mamelons
incisal edge is a rather flattened and sharp surface typically after tooth use
cej cementonamel junction (hint: main difference from other teeth)
curvature is even towards the incisal
cej on mx ci shows greatest depth of curve compared to any tooth surface (mesial)
mesial view labial surface traits vs palatal surface outline of mx ci
usually incisal 2/3 is flat for labial surface
usually concave at incisal 2/3 and convex at cervical 1/3 for lingual surface
what are shovel shaped incisors?
used to describe mx incisors with deep lingual fossa and prominent marginal ridges
where is the lingual height of contour on the mx ci? (imagine the palatal surface)
cervical 1/3
difference between mesial and distal surface of the mx ci
distal surface is shorter and more convex incisocervically
cej on the distal surface is less deep than on the mesial surface (mesial surface cej of mx ci shows greatest depth compared to any other tooth)
mx li crown outline form in labial view
trapezoidal
general dimensions of mx li
narrower than mx ci
root length > crown length
mx li trends
greater morphological variation in the facial crown shape
crown roundness
compare w mx ci
distal vs mesial outline form of mx li crown in labial view
distal outline form of mx li is more rounded than mesial
but both are rounder than in the mx ci
also compare w mx ci
mesio vs distoincisal angle of mx li
mesioincisal angle is more rounded than in mx ci but it is still an acute angle
same for distoincisal angle with the roundness, but it is still an obtuse angle
also compare with mx ci
mesial vs distal proximal contacts on mx li
**both are ** more cervically located than in mx ci
mesial prox contact is still located more coronal than distal prox contact
mesial prox contact is located at the junction of incisal 3rd w mid 3rd = ovoid
distal prox contact is in mid 3rd
are there facial developmental depressions and imbrication lines on mx li though?
YES
Incisal view of mx li
rhomboidal appearance of a canine with mesio distal dimension > faciolinguo dimension
mesial vs distal marginal ridges of mx li
mesial marginal ridge longer and straighter than distal marginal ridge just like in mx ci
compare with mx ci
what makes the lingual fossa of mx li different?
deeper and smaller -> harder to clean
frequently has a palatal or lingual pit at the incisal border of the cingulum
height of contour of mx ci
cervical 3rd of the tooth
is it very different from the mx ci?
where is the incisal ridge / edge located on the mx li?
along long axis of the tooth or just labial to it just like in mx ci
difference from mx ci?
mesial crown outline form of mx li
triangular, v shaped, wedge shaped. chisel shaped
